The field of the disclosure relates generally to power converters, and, more specifically, to battery integrated isolated power converters for hybrid-electric or all-electric vehicle propulsion systems.
In large vehicles such as aircraft, it is beneficial for hybrid-electric or all-electric propulsion, power converter, and energy storage systems to maximize the specific power, i.e., kilowatts per kilogram (kW/kg) of these components of the power system. To improve performance of propulsion systems, the specific power values of known power converters for hybrid-electric or all-electric vehicle propulsion must be increased. Moreover, known power converters for hybrid-electric or all-electric vehicle propulsion systems need to reliably supply power to critical propulsion equipment at all times, without being impacted whatsoever by power needs of, or electrical faults in accessory systems. In such known power converters for hybrid-electric or all-electric vehicle propulsion systems, interrupting power to the least number of electrical load components as possible is problematic and often results in diminished performance of the main propulsion system due to faults in individual non-propulsion accessory equipment.
At least some known power converters for hybrid-electric or all-electric vehicle propulsion systems utilize modular multi-level converter (MMC) architecture. Controllers for MMCs in such known power converters for hybrid-electric or all-electric vehicle propulsion systems must not only switch the MMC submodules, including those with insulated-gate bipolar transistors (IGBTs) or MOSFETs, they must also implement complex control algorithms with sophisticated high speed computing and communications to continually balance the voltages of each submodule capacitor.
The MMCs of such known power converters for hybrid-electric or all-electric vehicle propulsion systems utilize large energy storage capacitors on each MMC valve submodule as independently controllable two-level converters and voltage sources for AC or DC electrical loads. Also, in such known power converters for hybrid-electric or all-electric vehicle propulsion systems, isolation of power system components such as batteries require large line frequency transformers for enhanced safety and reduction of common mode interference. Many of these known power converters for hybrid-electric or all-electric vehicle propulsion systems utilize heavy and bulky passive components, e.g., capacitors and inductors, amounting to more than half of their weight.